Microsoft's Office365 Limits Emails to 500 Recipients a Day
zdnet.com
zdnet.com
And it's been that way for at least three years (I had written some code in 2008 to use multiple Apps accounts to send notifications for a web app in round-robin fashion)
"Michael Atalla, Director of product management for Exchange Server and Exchange Online, confirmed the limitation [...], arguing that it’s a necessary anti-spam measure:
'Every online service provider must limit and constrain its service based on limitations such as the amount of disk space currently in its datacenters or bandwidth currently available and also enforce behavioral thresholds which prevent inappropriate use of the service by malicious users or criminals. This is true for any form of web-based service.
In the world of email, one of the thresholds that must be enforced is the amount of email that is sent through the system by any one user or organization in order to combat spam, mass-mailing worms & viruses.'"
In this case I'd suggest they're being penalised for not reading the limitations before recommending a product to their client, and not double-checking that the service met the client's requirements.
Or like how you bought that vista home basic version of windows and it didn't even have administrator tools enabled.